Researchers identify chemical, physical traits of fallout. (Phys.org) —Lawrence Livermore National Laboratory researchers have begun to develop a technique that provides a practical approach for looking into the complex physical and chemical processes that occur during fallout formation following a nuclear detonation. Post-detonation nuclear forensics relies on advanced analytical techniques and an understanding of the physio-chemical processes associated with a nuclear detonation to identify the device type and the source of the nuclear material in the device. Fallout is a material formed from a cooling fireball following a detonation, in which unburned fuel, structural material and associated fission and activation products are incorporated with surrounding environmental material such as water, dust and soil.
The team used a small-scale electric arc apparatus to generate uranium-containing plasma in air. Explore further: Mathematician drafts urban nuclear shelter guide. High-pressure crystal structures of actinide elements to 100 GPa - Abstract - Journal of Physics: Condensed Matter. The structural behaviour of the actinide metals with pressure is being studied using diamond-anvil cells and the high-brilliance and angle-dispersive techniques now available at the ID30 beamline of the European Synchrotron Radiation Facility. A review is given of recent work at room temperature and up to 100 GPa. The results illustrate clearly the difference between the earlier metals (Pa, U) and those further across the actinide series (Am, Cm, and Cf). The complex structures at atmospheric pressure of the lighter actinides are a consequence of itinerant 5f electrons, and these metals show less compressibility (i.e. exhibit larger bulk moduli) and few (if any) phase transitions under pressure.
In contrast, the transplutonium metals do not have 5f electrons contributing to their cohesive energies at atmospheric pressure, are therefore 'soft' (have lower bulk moduli), and show multiple phase transitions before their 5f electrons become itinerant. 1312.7584. GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Next Big Future.